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RATIONALE: Angelman syndrome (AS) is an uncommon genetic disease characterized as serious retarded mental development and ocular abnormality. PATIENT CONCERNS: This report aims to present the ophthalmological features, and identify the diagnosis and outcomes of strabismus surgery in AS patients. DIAGNOSIS: Three children with exotropia were diagnosed with AS based on their typical clinical features. INTERVENTIONS: All patients underwent multiplex ligation-dependent probe amplification (MLPA) analysis and accepted lateral rectus recession surgery with the assistance of intravenous combined inhalation anesthesia. OUTCOMES: The maternal heritage deletion of chromosome 15q11.2-q13 was verified in all patients by MLPA. All patients with strabismus could not cooperate during the vision test, and had astigmatism. The strabismus type of AS patients was horizontal exotropia, and no vertical strabismus was found. One of these patients was combined with high myopia. The hypopigmentation on the hair and iris was ubiquitous. However, retina pigmentation was normal. After different degrees of lateral rectus recession, the exotropia was significantly relieved, and the surgical effects were stable postoperatively. LESSONS: Horizontal exotropia is the major strabismus type. Severe intellectual disability, hyperactivity, and speech impairment are the common characteristics of AS children. Its examination and operation design remains challenging. Thus, repeated examinations and intelligence rehabilitation are essential.

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PURPOSE: It is well known that the dopaminergic signaling pathway plays a pivotal role in the control of axial elongation. Much research has shown that retinal dopamine (DA) is decreased in experimental myopia, but the exact alteration in DA quantity underlying the myopia model induced by flickering light (FL) has not yet been fully elucidated. Therefore, in this study, we first attempted to prove the feasibility of the myopia model induced by FL and then to determine whether and how DA and its receptors changed in myopia induced by FL. METHODS: Forty-five 2-week-old guinea pigs were randomly divided into three groups, as follows: the control group, form-deprivation myopia (FDM) group, and FL-induced myopia (FLM) group. Animals in the control and FDM groups were raised under normal illumination, and the right eyes of the FDM group were covered with semitransparent hemispherical plastic shells serving as eye diffusers. Guinea pigs in the FLM group were raised under illumination with a duty cycle of 50% at a flash rate of 0.5 Hz. The refraction, axial length (AL), and corneal radius of curvature (CRC) were measured using streak retinoscopy, A-scan ultrasonography, and keratometry, respectively, before and after 2, 4, 6, and 8 weeks of treatment. The contents of DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in the retina, vitreous body, and RPE were measured at the end of the 8-week experiment using high-performance liquid chromatography (HPLC). The numbers of retinal D1 DA receptor (D1DR) and D2 DA receptor (D2DR) were evaluated via immunohistofluorescence and western blot assay. RESULTS: The refraction of the FLM group became more myopic throughout the experimental period, which was mainly indicated by decreased refraction and a longer AL compared with the control group (p<0.05). The contents of DA, DOPAC, and HVA in the retina, vitreous body, and RPE of the FLM group were significantly increased, but decreased in the FDM group, compared with those of the control group (both p<0.05). Like form-deprived eyes, the expressions of retinal D1DR and D2DR in FL eyes were significantly upregulated compared with controls (p<0.05). CONCLUSIONS: Myopia can be induced by 0.5-Hz FL in guinea pigs at puberty. Contrary to FDM, dopaminergic neuron activity and DA release were significantly elevated in FLM. Like in FDM, the expressions of D1DR and D2DR were upregulated in FLM. Thus, the results of our study may further demonstrate that the DA system is associated with the development of myopia.

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AIM: To select the optimal edge detection methods to identify the corneal surface, and compare three fitting curve equations with Matlab software. METHODS: Fifteen subjects were recruited. The corneal images from optical coherence tomography (OCT) were imported into Matlab software. Five edge detection methods (Canny, Log, Prewitt, Roberts, Sobel) were used to identify the corneal surface. Then two manual identifying methods (ginput and getpts) were applied to identify the edge coordinates respectively. The differences among these methods were compared. Binomial curve (y=Ax2+Bx+C), Polynomial curve [p(x)=p1xn+p2xn-1 +....+pnx+pn+1] and Conic section (Ax2+Bxy+Cy2+Dx+Ey+F=0) were used for curve fitting the corneal surface respectively. The relative merits among three fitting curves were analyzed. Finally, the eccentricity (e) obtained by corneal topography and conic section were compared with paired t-test. RESULTS: Five edge detection algorithms all had continuous coordinates which indicated the edge of the corneal surface. The ordinates of manual identifying were close to the inside of the actual edges. Binomial curve was greatly affected by tilt angle. Polynomial curve was lack of geometrical properties and unstable. Conic section could calculate the tilted symmetry axis, eccentricity, circle center, etc. There were no significant differences between 'e' values by corneal topography and conic section (t=0.9143, P=0.3760 >0.05). CONCLUSION: It is feasible to simulate the corneal surface with mathematical curve with Matlab software. Edge detection has better repeatability and higher efficiency. The manual identifying approach is an indispensable complement for detection. Polynomial and conic section are both the alternative methods for corneal curve fitting. Conic curve was the optimal choice based on the specific geometrical properties.

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AIM: To investigate the intraocular pressure (IOP) of adult guinea pig eyes with rebound tonometry (RBT), and assess the effects of four distinctive topical IOP reducing medications including Carteolol, Brimonidine, Brinzolamide and Latanoprost. METHODS: The IOPs of twenty-four 12-week-old guinea pigs (48 eyes) were measured every two hours in one day with RBT as baselines. All the animals were then divided into four groups (Carteolol, Brimonidine, Brinzolamide and Latanaprost groups, n=6). The IOPs were measured and compared to the baseline 1, 2, 3, 5, 7, 9, 15 and 24h after treatment. RESULTS: The mean baseline IOP of 24 guinea pigs (48 eyes) was 10.3±0.36 mm Hg (6-13 mm Hg) and no binocular significant differences of IOPs were observed (t=1.76, P>0.05). No significant difference of IOP in Carteolol group at each time point was observed before and after treatment (t=1.48, P>0.05). In Brimonidine group, IOP was 2.2±1.9 mm Hg lower than the baseline after one hour (t=3.856, P=0.003) and lasted for one hour. In Brinzolamide group, IOP was 1.4±1.1 mm Hg lower than the baseline after one hour (t=4.53, P=0.001) and lasted for 7h and the IOP declined most at 3h. In Latanaprost group, IOP was 2.1±1.3 mm Hg lower than the baseline after one hour (t=6.11, P=0.001) and lasted for one hour. CONCLUSION: The IOP of guinea pig eyes is relatively stable compared to human eyes. In four reducing IOP medications, no significant effect of Carteolol is observed. Brinzolamide has the longest duration, while the Brimonidine has the shortest duration and the maximum level of treatment.

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Studies in mammals have shown that damaged DNA-binding protein 1 (DDB1) is a multifunctional protein that recognizes UV-induced DNA lesions and activates nucleotide excision repair process, and could also be a linker protein for Cullin4 in ubiquitination to regulate cell cycle progression. However, there are few studies of DBB1 in crustaceans. In this study, a cDNA representing the DDB1 gene from Eriocheir sinensis (Es-DDB1) was cloned successfully. The full length Es-DDB1 cDNA comprises 4871 nucleotides, and encodes an open-reading frame (ORF) of 1137 amino acid residues. Bioinformatics' analysis showed that the domains and structure of Es-DDB1 have been highly conserved during evolution. Antibodies against Es-DDB1 and Es-Cul4 were raised using a prokaryotic expression system. Moreover, a co-immunoprecipitation assay showed that Es-DDB1 could bind Es-Cul4 in the testis of Eriocheir sinensis. Furthermore, quantitative real-time PCR and Western blotting showed high expression in the testis, particularly during the spermatocyte stage. Immunofluorescence assays showed that Es-DDB1 was mainly distributed in the cytoplasm in the early and middle developmental stages. These results indicated that Es-DDB1 might play a key role in spermatogenesis of E. sinensis.

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Heme {Fe(II)- or Fe(III)-protoporphyrin IX complex [heme(Fe(2+)) or heme(Fe(3+)), respectively]} binds selectively to the 3'-terminal G-quartet of a parallel G-quadruplex DNA formed from a single repeat sequence of the human telomere, d(TTAGGG), through a π-π stacking interaction between the porphyrin moiety of the heme and the G-quartet. The binding affinities of some chemically modified hemes(Fe(3+)) for DNA and the structures of complexes between the modified hemes(Fe(2+)) and DNA, with carbon monoxide (CO) coordinated to the heme Fe atom on the side of the heme opposite the G6 G-quartet, have been characterized to elucidate the interaction between the heme and G-quartet in the complexes through analysis of the effects of the heme modification on the structural properties of the complex. The study revealed that the binding affinities and structures of the complexes were barely affected by the heme modification performed in the study. Such plasticity in the binding of heme to the G-quartet is useful for the versatile design of the complex through heme chemical modification and DNA sequence alteration. Furthermore, exchangeable proton signals exhibiting two-proton intensity were observed at approximately -3.5 ppm in the (1)H nuclear magnetic resonance (NMR) spectra of the CO adducts of the complexes. Through analysis of the NMR results, together with theoretical consideration, we concluded that the heme(Fe(2+)) axial ligand trans to CO in the complex is a water molecule (H2O). Identification of the Fe-bound H2O accommodated between the heme and G-quartet planes in the complex provides new insights into the structure-function relationship of the complex.

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BACKGROUND: The aim was to investigate various levels of stroboscopic illumination effect on the growth of guinea pig eyes. METHODS: Thirty-six two-week-old guinea pigs were randomised to one of three treatment groups (n = 12 for each). Two stroboscopic-reared groups were raised with a duty diurnal cycle of 50 per cent at a flash rate of 0.5 Hz. Illumination intensity varied between zero-to-250 lux or zero-to-500 lux during each cycle in each group, respectively. The third control group was exposed to 250 lux illumination. Refraction and biometric measurements were taken for each animal prior to and after two, four, six and eight weeks of treatment. Finally, retinal microstructure was examined. RESULTS: There was significant correlation between refractive errors and axial elongation. After eight weeks of treatment, illumination with flickering light 0-250 lux caused a larger myopic shift with increased axial length than illumination of continuous 250 lux. Stroboscopic illumination with zero-to-500 lux caused a further myopic shift and longer axial length than stroboscopic illumination with zero-to-250 lux. In animals raised in flickering light of zero-to-250 lux or zero-to-500 lux for eight weeks, the outer segment disc membranes in photoreceptor layers were found deformed and detached. CONCLUSION: Chronic exposure to low-frequency temporally modulated illumination-induced histological damage in the retina and induced exaggerated axial length elongation.

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AIMS: To investigate the effect of prolonged flickering illumination exposure on the growth of the guinea pig eye. METHODS: Thirty-six 2-week-old guinea pigs were randomized to one of the three treatment groups (n = 12 for each). Two strobe-reared groups were raised with a duty diurnal cycle of 50 % at a flash rate of 0.5 Hz and 5 Hz respectively. Illumination intensity varied between the minimum-maximum light levels of 0-600 lux during each cycle. The control group was exposed to steady 300 lux illumination. All animals underwent refraction and biometric measurements prior to and after 2, 4, 6, 8, 10 and 12 weeks of treatment. Finally, flash electroretinograms were compared, and retinal microstructures were examined. RESULTS: There was a significant correlation between refractive errors and axial eye elongation, with myopia increasing between 1.5 and 3.4 D per mm eye elongation. After 12 weeks of treatment, the animals raised in 0.5 Hz flickering light were 5.5 ± 0.4 D more myopic than the group raised in continuous illumination, followed by the group raised at 5 Hz flicker light which was about 2.2 ± 1.3 D more myopic. In animals raised in flickering light of 5 or 0.5 Hz for 12 weeks, the implicit time of the a-wave was delayed by 4 and 8.5 ms, respectively. At this time, the outer segment disc membranes were found deformed and detached. CONCLUSION: Chronic exposure to 0.5 and 5 Hz temporally modulated illumination induces electrophysiological and histological changes in retinal activities that alter the emmetropization of the guinea pig eye.

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AIM: To investigate the effectiveness and feasibility of inducing myopia in guinea pigs by flickering light (FL) stimulation with different frequencies. METHODS: Seventy 2-week-old guinea pigs were randomly assigned to six groups: five FL groups and a control group (n=12 for each). Animals in the five FL groups were raised under 500lx illumination with a duty diurnal cycle of 50% at a flash rate of 5, 1, 0.5, 0.25 and 0.1Hz respectively. Those in the control group were reared under steady 250lx illumination. Refraction, axial length, and radius of curvature were measured before and at 2, 4, 6, 8, 10 and 12 weeks after treatment. At week 12, the eyeballs were taken out and three ocular dimensions and dry weight of sclera were measured. RESULTS: A myopic shift and axial eye length increase developed in the five FL groups. Stimulation at 0.5Hz caused greater changes in myopic shift, axial elongation, eyeball dimension, and dry weight of sclera than stimulation at other frequencies. Compared with controls, eyes in 0.5Hz group were approximately -5.5±1.5D more myopic with increase in horizontal, vertical, axial dimensions by 0.89±0.3mm, 0.69±0.2mm, 1.12±0.2mm respectively and with increase in dry weight of sclera by 0.44mg. CONCLUSION: Chronic exposure to periodic illumination at temporal frequency is attended by development of excessive ocular enlargement and myopic refractive error. Emmetropization could be disrupted differently by frequency alteration.

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When eyeball fixes targets, it will produce one frequent and regular movement which is difficult to detect. Such movements is called fixation eye motion. This motion can be further divided into drift, tremor and microsaccades. In recent years, research in this field is strikingly increasing. Due to the significant role on the control of fixation positron, maintaining continuous sense of perception, keeping bistable condition, clear vision, spatial orientation and attention, research in this field is maybe a worthwhile myopia research direction.

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RATIONALE AND OBJECTIVES: The aim of this study was to investigate the effect of perfusion computed tomography (PCT) with acetazolamide (ACZ) challenge and compare it to 10% carbon dioxide (CO(2)) challenge in rat C6 glioma. MATERIALS AND METHODS: PCT was performed on 32 rats, including 20 with orthotopically implanted C6 gliomas and 12 serving as controls. Ten rats with gliomas and six normal rats underwent PCT with ACZ challenge. The other 10 rats with gliomas and six normal rats underwent PCT with 10% CO(2) challenge. The raw data were processed using Philips computed tomographic brain perfusion software. Perfusion parameters before and after the challenge were recorded. Percentage changes due to ACZ administration and 10% CO(2) challenge were calculated. Pearson's correlation coefficients were used to investigate relationships between percentage changes in perfusion parameters and vascular endothelial growth factor and microvessel density. RESULTS: In C6 gliomas, percentage change in cerebral blood flow was significantly different between ACZ (72.73%) and 10% CO(2) (28.47%) challenge (P < .01). Percentage change in cerebral blood volume was 37.85% with ACZ and 24.69% with 10% CO(2) challenge (P = .02). In controls, percentage change in cerebral blood flow was significantly different between ACZ (117.42%) and 10% CO(2) (65.86%) challenge (P < .01). For percentage change in cerebral blood volume, there was no significant difference between ACZ (107.51%) and 10% CO(2) (92.95%) challenge. Significant correlations were observed among percentage changes in vascular endothelial growth factor, microvessel density, and cerebral blood volume (P < .01). Percentage change in cerebral blood flow correlated well with vascular endothelial growth factor. CONCLUSIONS: The results of this study indicate that PCT with ACZ challenge is a more reliable technique compared to 10% CO(2) challenge for the quantitative evaluation of microcirculation in gliomas.

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OBJECTIVE: To investigate the dose-effect relationship between the radiation of ultraviolet ray and the onset of pterygium quantitatively. METHODS: Interrogation was conducted to 95 patients with pterygium in Yacheng district, Sanya City, Hainan Province, 37 males and 58 females, aged 55.7 +/- 13.8 (20 - 80), and 95 local volunteers in 1:1 pairs matched in age, sex, race, and similar habits of wearing glasses and caps (control group). Both the pterygium group and control group were re-divided into three sub-groups: youth (aged < or = 40), middle-aged (aged 41 - 60), and elderly (aged > 60). The time of exposing to ultraviolet ray was calculated. Photo of the pterygium was taken. The length of the pterygium invading into cornea was measured. RESULTS: The ultraviolet ray exposure time of the youth subgroup, pterygium group, was 35,637 +/- 13,587 hours, significantly higher than that of the youth subgroup, control group (26,188 +/- 17,423 hours, t = 3.352, P = 0.006). The ultraviolet ray exposure time of the middle-aged subgroup, pterygium group, was 73,412 +/- 23,082 hours, significantly higher than that of the middle-aged subgroup, control group (63,368 +/- 25,091 hours, t = 2.322, P = 0.024). However, there was no significant difference in the ultraviolet ray exposure time between the elderly subgroups of both groups. The length of the pterygium invading into cornea was positively correlated with the ultraviolet ray exposure time (r = 0.361, P < 0.05), and the length showed a trend of increased with aging. CONCLUSION: There is a certain dose-effect correlation between ultraviolet ray exposure and the etiology of pterygium.

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